Eye on Ophthalmology

A modified chondroitin sulfate aldehyde adhesive for sealing corneal incisions.

2006-08-21T06:42:00.000-07:00

Invest Ophthalmol Vis Sci. 2005 Apr;46(4):1247-50.

Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

PURPOSE: To compare a modified chondroitin sulfate aldehyde adhesive with standard sutures for sealing corneal incisions. METHODS: A keratome knife was used to create non-self-sealing, uniplanar, 3-mm, clear corneal incisions in enucleated rabbit eyes (n = 18). The wounds were sealed with either a chondroitin sulfate-aldehyde adhesive (n = 8), three 10-0 nylon sutures (n = 5), or one 10-0 nylon suture (n = 5). Wound stability was tested by filling the globes with balanced salt solution through an anterior chamber port and slowly increasing the IOP. The pressure changes were monitored with a digital manometer connected to the anterior chamber, and leak pressure was recorded for each eye. Confocal microscopy was performed on the glued eyes, to document the glue distribution along the wound. RESULTS: The mean leak pressures in the single-suture and three-suture subgroups were 26.4 +/- 6.0 and 44.3 +/- 8.2 mm Hg (SD), respectively. The maximum IOP achieved in eyes that received the glue was 104.7 mm Hg with a mean of 101.4 +/- 3.2 mm Hg. None of the eyes in which glue was used showed leakage. At confocal microscopy, the glue was distributed inside the wound edges as a homogeneous thin layer of a less dense signal than that of the stroma. CONCLUSIONS: A novel chondroitin sulfate-aldehyde adhesive was shown to be effective ex vivo for sealing corneal incisions in rabbit eyes and was superior to sutures for this purpose.

PMID: 15790885 [PubMed - indexed for MEDLINE]

Comparison of fibrin glue and sutures for attaching conjunctival autografts after pterygium excision.

2006-08-21T06:41:00.000-07:00

Ophthalmology. 2005 Apr;112(4):667-71.

Department of Ophthalmology and Visual Sciences, University of the Philippines, Philippine General Hospital, Manila, Philippines. harveyuy@yahoo.com

PURPOSE: To compare the efficacy and safety of fibrin glue and suturing for attaching conjunctival autografts among patients undergoing pterygium excision. DESIGN: Prospective, randomized, interventional case series. PARTICIPANTS: Twenty-two patients undergoing excision of primary pterygium. METHODS: A superior conjunctival autograft was harvested and transferred onto bare sclera after pterygium excision. Fibrin glue (Beriplast P) was used to attach the autograft in 11 eyes and nylon 10-0 suture was used to attach the autograft in 11 eyes. The patients were followed up for 2 months. MAIN OUTCOME MEASURES: Graft success, recurrence rate, operating time, patient comfort. RESULTS: All conjunctival autografts in both groups were successfully attached and were intact after 2 months. The average operating time for the fibrin glue group was significantly shorter (P<0.001).>

PMID: 15808260 [PubMed - indexed for MEDLINE]

Noninvasive mitochondrial imaging in live cell culture.

2006-08-21T06:40:00.001-07:00

Photochem Photobiol. 2005 Nov-Dec;81(6):1569-71.

Department of Ophthalmology, Johns Hopkins University, Baltimore, MD 21117, USA.

The observed distribution of mitochondria in a cell can vary with environmental influence, degree of differentiation and disease. Differences in the distribution of mitochondrial autofluorescence may be used to distinguish these different cellular states.

PMID: 16156691 [PubMed - indexed for MEDLINE]

Inflow of ocular surface fluid into the anterior chamber after phacoemulsification through sutureless corneal cataract wounds.

2006-08-21T06:39:00.000-07:00

Am J Ophthalmol. 2005 Oct;140(4):737-40.

Wilmer Ophthalmological Institute, The Johns Hopkins Hospital, Baltimore, Maryland 21287-9278, USA.

PURPOSE: To report inflow of extraocular fluid after phacoemulsification with use of sutureless corneal incisions. DESIGN: Interventional case series. METHODS: setting: Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland. patients: Eight patients (three women), aged 58 to 91 years, showing minimal bleeding from the limbal capillary bed during phacoemulsification. intervention: Surgery was performed through a 2.8-mm limbal incision. External pressure simulating patient manipulation was applied before and after wound hydrosealing with an irrigation cannula. main outcome measures: Inflow of blood-tinged tear fluid into the anterior chamber through the wound was monitored by using digital video. RESULTS: Inflow of extraocular fluid was observed in all eyes when the cannula was released, even after wound hydrosealing. Two patients showed spontaneous fluid inflow. CONCLUSIONS: Tested sutureless corneal incisions allow inflow of extraocular fluid into the anterior chamber after phacoemulsification. This may permit intraocular contamination leading to endophthalmitis.

PMID: 16226532 [PubMed - indexed for MEDLINE]

Botulinum toxin B-induced mouse model of keratoconjunctivitis sicca.

2006-08-21T06:37:00.000-07:00

Invest Ophthalmol Vis Sci. 2006 Jan;47(1):133-9.

Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, Maryland 21286, USA.

PURPOSE: To develop a mouse model of human chronic dry eye (keratoconjunctivitis sicca [KCS]). METHODS: Under direct visualization with an operating microscope, CBA/J mice received a transconjunctival injection of saline or 1.25, 5, or 20 milliunits (mU) of botulinum toxin B (BTX-B) into the lacrimal gland. The mice were either left unstressed or were subjected to an air blower for 5 h/d, 5 d/wk in fixed temperature and humidity conditions. Tear production and corneal fluorescein staining were evaluated in all groups before injection and at several time points after. Tear production was measured with phenol red-impregnated cotton threads. Corneal fluorescein staining was photographed under cobalt blue light with a digital camera fitted with a macro lens. RESULTS: BTX-B-injected mice displayed significantly decreased tear production until the 4-week time point. Throughout all time points, the addition of environmental blower stress did not appear to alter tear production significantly. Linear regression models, used to evaluate the effects of various doses of BTX-B on tear production, showed that doses higher than 1.25 mU did not provide significantly different outcomes. After 3 days, saline-injected mice showed no corneal staining, whereas BTX-B-injected mice displayed various amounts of staining. At the early time point (day 3), there did not appear to be an additional effect of the blower on corneal fluorescein staining. However, at 1, 2, and 4 weeks, the blower stress appeared to increase the amount of corneal fluorescein staining at each BTX-B dose, although not significantly. Furthermore, at 8 to 10 weeks, in the BTX B-injected groups, corneas had persistent staining, even though tear production had already returned to normal levels. Histopathologic analyses revealed no inflammatory cell infiltration of the stroma or acini of the lacrimal glands and conjunctivae of both saline-injected and BTX-B-injected animals. CONCLUSIONS: Intralacrimal gland injection of BTX-B resulted in persistent corneal fluorescein staining within 3 days, and a significant decrease in aqueous tear production that persisted for 1 month. Intralacrimal gland injection of BTX-B suppressed lacrimation, thereby establishing a dry eye state. This animal model could be a useful tool for investigating the pathogenesis of the chronic condition KCS in humans.

PMID: 16384954 [PubMed - indexed for MEDLINE]

Metabolic changes in mesenchymal stem cells in osteogenic medium measured by autofluorescence spectroscopy.

2006-08-21T06:36:00.000-07:00

Stem Cells. 2006 May;24(5):1213-7. Epub 2006 Jan 26.

Department of Ophthalmology, Johns Hopkins University, Baltimore, Maryland 21117, USA.

The purpose of this study was to measure metabolic changes in mesenchymal stem cells (MSCs) placed in osteogenic medium by autofluorescence spectroscopy. MSCs were plated in stem cell-supporting or osteogenic medium and imaged. Shift from the basic growth environment to the inductive osteogenic environment was confirmed by reverse transcription-polymerase chain reaction. Reduced pyridine nucleotides were detected by exciting near 366 nm and measuring fluorescence at 450 nm, and oxidized flavoproteins were detected by exciting at 460 nm and measuring fluorescence at 540 nm. The ratio of these fluorescence measurements, reduction-oxidation (redox) fluorometry, is a noninvasive measure of the cellular metabolic state. The detected pyridine nucleotide to flavoprotein ratio decreased upon transitioning from the stem cell to the differentiated state, as well as with increasing cell density and cell-cell contact. MSC metabolism increased upon placement in differentiating medium and with increasing cell density and contact. Redox fluorometry is a feasible, noninvasive technique for distinguishing MSCs from further differentiated cells.

PMID: 16439616 [PubMed - in process]

Modified microkeratome-assisted posterior lamellar keratoplasty using a tissue adhesive.

2006-08-21T06:35:00.000-07:00

Arch Ophthalmol. 2006 Feb;124(2):210-4.

Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD 21287-9278, USA.

OBJECTIVE: To compare graft stability and astigmatic change using suture vs tissue adhesive in an experimental model of microkeratome-assisted posterior lamellar keratoplasty. METHODS: A 300-microm-thick partial flap keratectomy was performed in human donor corneoscleral rims using an artificial anterior chamber and a manual microkeratome. The flap stopped at the left central opening border, providing a wide hinge to add stability. After flap reflection, a 6.25-mm trephination was performed to obtain a disc of posterior stroma, Descemet membrane, and endothelium. The disc was positioned in a sutureless fashion, and the flap secured with either 5 interrupted sutures or a chondroitin-sulfate-aldehyde-based adhesive. Increasing intrachamber pressures were created to detect graft stability. Videokeratographic data were recorded to evaluate astigmatic change. RESULTS: The mean (SD) astigmatic change was 3.08 (0.84) diopters (D) in the sutured group and 1.13 (0.55) D in the glued group (P = .008). Mean (SD) resisted pressures were 95.68 (27.38) mm Hg and 82.45 (18.40) mm Hg in the sutured and glued groups, respectively (P = .97). CONCLUSION: This modified technique of microkeratome-assisted posterior lamellar keratoplasty showed excellent graft stability in both groups. Flaps sealed with the novel tissue adhesive had reduced astigmatic changes in our experimental model. CLINICAL RELEVANCE: Sutureless microkeratome-assisted posterior lamellar keratoplasty using tissue adhesive may become a new alternative in the surgical treatment of corneal endothelial disorders.

PMID: 16476891 [PubMed - indexed for MEDLINE]

Use of topical human amniotic fluid in the treatment of acute ocular alkali injuries in mice.

2006-08-21T06:28:00.000-07:00

Am J Ophthalmol. 2006 Aug;142(2):271-8.

The Wilmer Ophthalmological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.

PURPOSE: To evaluate the efficacy of topical human amniotic fluid (HAF) in the treatment of ocular acute alkali burns in mice. DESIGN: Experimental study. METHODS: A chemical burn with 2 microl of sodium hydroxide 0.15 mol/l was created in one eye of 30 mice. The animals were divided into gender- and age-matched groups according to the topical treatment that was administered: group 1 was treated with preterm HAF (n = 10 mice); group 2 was treated with term HAF (n = 10 mice), and group 3 was treated with saline solution (n = 10 mice). Treatment consisted of one drop that was applied to the burned eye five times per day (week one), and three times per day (week two). The epithelial defect was photographed and measured on days two and four. Ocular burn damage was assessed at days two, seven, and 14 after a pre-established classification. On day 14, both eyes of each mouse were enucleated and assessed histopathologically. RESULTS: Median epithelial defect (interquartile range [IQR], 25th, 75th percentile) at day four was 9.93% (IQR, 8.57, 11.27) for group 1, 7.30% (IQR, 5.96, 8.97) for group 2, and 18.92% (IQR, 11.71, 27.64) for group 3 (P < .0076). The overall change (difference in slope) in ocular burn score between days 2 and 14 was -0.127 (P = .009) in group 1 vs 3, -0.134 (P = .012) in group 2 vs 3, and 0.007 (P = .88) in group 1 vs 2. On histologic examination saline solution-treated corneas had more inflammatory cells and blood vessels than HAF-treated corneas. CONCLUSION: Topical preterm/term HAF was an effective topical therapy for limiting the damage after acute alkali burns of the eye in this animal model.

PMID: 16876508 [PubMed - in process]